JOHANNESBURG -- At first glance they are nothing alike. Zimbabwe's aging president, Robert Mugabe, is, at 84, among the last of a generation of African Big Men, clinging to power through brutal repression. South Africa's suave President Thabo Mbeki, nearly two decades younger, rules by popular mandate as the elected leader of one of the continent's most robust democracies.

But Mbeki's long -- and so far, failed -- diplomatic bid to ease Mugabe into retirement after 28 years has tied the legacies of the two men together, and badly damaged Mbeki's reputation as the exemplar of a new kind of African president. The leader President Bush described as "the point man" on solving the Zimbabwe crisis in 2003 now is widely regarded as an obstacle to freeing that nation from its steep descent into political and economic ruin.

"I think he's part of the problem at the moment," said Willie Esterhuyse, a Mbeki friend and a professor of political philosophy at the University of Stellenbosch.

Mbeki is one of a dwindling number of African leaders unwilling to publicly distance himself from Mugabe. The two men are products of strikingly similar worlds. Both are Christian-school-trained products of African liberation movements and have deep roots in communist ideology. Both have advanced degrees from British universities and rose within their parties on the strength of wits and political savvy rather than prowess on battlefields. Neither favors the traditional African dress worn by many of the continent's leaders, appearing almost invariably in dark, tailored suits. And both enjoyed periods as favorites of Western powers, which for a time regarded each as skilled and cerebral alternatives to the populists common on much of the continent.

Mugabe's seizure of white-owned commercial farms in 2000 also struck a profound chord in southern Africa, where much of the best land and businesses remain in the control of descendants of European settlers. At Mbeki's second inauguration, in 2004, the crowd of friends, supporters and dignitaries loudly cheered Mugabe.

Such a reaction would be unlikely today, as rising repression in Zimbabwe chills even those sympathetic to Mugabe's efforts to redistribute wealth and undo the legacy of colonialism. Mbeki is almost alone among southern African leaders in not publicly voicing outrage.

Biographer Mark Gevisser, in his book "Thabo Mbeki: The Dream Deferred," tells an anecdote that suggests an almost familial bond between the two men.

In 1980, shortly after Mugabe took power in Zimbabwe, Mbeki was there as an emissary for South Africa's exiled African National Congress. One night, he stayed out late drinking in Harare, the capital. His frantic wife reported Mbeki missing, a worrisome development at a time when South Africa's apartheid government was attempting to assassinate its opponents.

The next time the two men saw each other, Mugabe delivered a paternalistic scolding, waving his finger as he said, "Young man, you must tell us next time you don't sleep at home."

The African National Congress had traditionally favored a rival of Mugabe's in Zimbabwe's liberation struggle. But Mbeki, in those days in exile, forged a new relationship between the party and Mugabe's new government. That connection still has a powerful hold on Mbeki, according to Gevisser, who said Mbeki remains convinced that he is essential to keeping Mugabe from growing still more brutal.

"Whatever happens, he has got to keep the door open," Gevisser said in an interview.

Officials in Mbeki's administration also have expressed deep reservations about Morgan Tsvangirai, leader of the Zimbabwean opposition. The former miner and union activist, though very popular in his country, has little formal education and has tried to organize the kind of internal political resistance that Mbeki's African National Congress used to bring down apartheid.

Mbeki long has enjoyed closer relations with other, more-polished opposition leaders in Zimbabwe, including Tsvangirai's rival, Welshman Ncube, a law professor.

In the just-finished election season, South African support was seen as crucial to the emergence of independent candidate Simba Makoni, Mugabe's former finance minister, who broke from the ruling party to run for president. Tsvangirai was able to maintain his position as Zimbabwe's dominant opposition leader -- Makoni ended up with only 8 percent of the vote -- but relations with Mbeki deteriorated further.

Mbeki "respects Mugabe," said Tendai Biti, secretary general of the Movement for Democratic Change, Tsvangirai's party. "He's personally indebted to Mugabe because he looked after him during the struggle" against apartheid.

Mbeki's approach has produced some moments that caused even supporters to cringe.

On April 12, when southern African regional leaders gathered in neighboring Zambia for an emergency meeting on the Zimbabwean crisis, Mugabe refused to attend but Mbeki met with him anyway, in Harare. Photographers captured the two men, dressed almost identically in suits, wearing necklaces of fresh blossoms, smiling broadly as they clasped hands like old friends. In a news conference that day, Mbeki questioned whether there was a "crisis" in Zimbabwe at all.

Also damaging was Mbeki's attempt to host a mediation session on July 5, a week after Mugabe had declared victory in a reelection campaign that left nearly 100 opposition activists dead and thousands of others injured. Tsvangirai withdrew from the election and said there could be no negotiations until the attacks on his supporters ended.

Mbeki ignored that condition and invited Tsvangirai to meet with Mugabe at his official residence, a setting that opposition leaders said would have conveyed an air of legitimacy to the election. Tsvangirai boycotted the meeting.

Swazi election observer Marwick T. Khumalo, a member of the Pan-African Parliament, said that proposing talks at Mugabe's residence showed "bad taste" on Mbeki's part.

Despite the failure of that meeting, negotiations of sorts have begun in Zimbabwe, under the oversight of South Africa. Though the opposition dismisses the talks as having no promise until Mugabe ends his campaign of state-sponsored violence, both sides acknowledge that in a nation with annual inflation measured in the millions of percent, there may be no other course.

Yet Mbeki's time for brokering a solution -- and removing the stain of Mugabe from his own legacy -- is rapidly dwindling. Mugabe, who continues to look remarkably vigorous for his age, could easily remain in office longer than Mbeki, whose second and final term as president is due to end in mid-2009.

Mbeki's legacy in Africa is "in tatters," said Karima Brown, political editor of the South African newspaper Business Day. "Thabo Mbeki is really yesterday's man. He's done."